XCEngine/engine/third_party/physx/source/lowleveldynamics/src/DySolverConstraintsShared.h

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#ifndef DY_SOLVER_CONSTRAINT_SHARED_H
#define DY_SOLVER_CONSTRAINT_SHARED_H

#include "foundation/PxPreprocessor.h"
#include "foundation/PxVecMath.h"

#include "DySolverBody.h"
#include "DySolverContact.h"
#include "DySolverConstraint1D.h"
#include "DySolverConstraintDesc.h"
#include "foundation/PxUtilities.h"
#include "DyConstraint.h"
#include "foundation/PxAtomic.h"


namespace physx
{

namespace Dy
{
	PX_FORCE_INLINE static FloatV solveDynamicContacts(const SolverContactPoint* PX_RESTRICT contacts, PxU32 nbContactPoints, const Vec3VArg contactNormal,
	const FloatVArg invMassA, const FloatVArg invMassB, const FloatVArg angDom0, const FloatVArg angDom1, Vec3V& linVel0_, Vec3V& angState0_, 
	Vec3V& linVel1_, Vec3V& angState1_, PxF32* PX_RESTRICT forceBuffer, Dy::ErrorAccumulator* PX_RESTRICT error)
{
	Vec3V linVel0 = linVel0_;
	Vec3V angState0 = angState0_;
	Vec3V linVel1 = linVel1_;
	Vec3V angState1 = angState1_;
	FloatV accumulatedNormalImpulse = FZero();

	const Vec3V delLinVel0 = V3Scale(contactNormal, invMassA);
	const Vec3V delLinVel1 = V3Scale(contactNormal, invMassB);

	for(PxU32 i=0;i<nbContactPoints;i++)
	{
		const SolverContactPoint& c = contacts[i];
		PxPrefetchLine(&contacts[i], 128);

		const Vec3V raXn = Vec3V_From_Vec4V(c.raXn_velMultiplierW);

		const Vec3V rbXn = Vec3V_From_Vec4V(c.rbXn_maxImpulseW);

		const FloatV appliedForce = FLoad(forceBuffer[i]);
		const FloatV velMultiplier = c.getVelMultiplier();
		const FloatV impulseMultiplier = c.getImpulseMultiplier();
		
		/*const FloatV targetVel = c.getTargetVelocity();
		const FloatV nScaledBias = c.getScaledBias();*/
		const FloatV maxImpulse = c.getMaxImpulse();

		//Compute the normal velocity of the constraint.
		const Vec3V v0 = V3MulAdd(linVel0, contactNormal, V3Mul(angState0, raXn));
		const Vec3V v1 = V3MulAdd(linVel1, contactNormal, V3Mul(angState1, rbXn));
		const FloatV normalVel = V3SumElems(V3Sub(v0, v1));

		const FloatV biasedErr = c.getBiasedErr();//FScaleAdd(targetVel, velMultiplier, nScaledBias);

		//KS - clamp the maximum force
		const FloatV _deltaF = FMax(FNegScaleSub(normalVel, velMultiplier, biasedErr), FNeg(appliedForce));
		const FloatV _newForce = FAdd(FMul(impulseMultiplier, appliedForce), _deltaF);
		const FloatV newForce = FMin(_newForce, maxImpulse);
		const FloatV deltaF = FSub(newForce, appliedForce);
		if (error)
			error->accumulateErrorLocal(deltaF, velMultiplier);

		linVel0 = V3ScaleAdd(delLinVel0, deltaF, linVel0);
		linVel1 = V3NegScaleSub(delLinVel1, deltaF, linVel1);
		angState0 = V3ScaleAdd(raXn, FMul(deltaF, angDom0), angState0);
		angState1 = V3NegScaleSub(rbXn, FMul(deltaF, angDom1), angState1);
		
		FStore(newForce, &forceBuffer[i]);

		accumulatedNormalImpulse = FAdd(accumulatedNormalImpulse, newForce);
	}

	linVel0_ = linVel0;
	angState0_ = angState0;
	linVel1_ = linVel1;
	angState1_ = angState1;
	return accumulatedNormalImpulse;
}

PX_FORCE_INLINE static FloatV solveStaticContacts(const SolverContactPoint* PX_RESTRICT contacts, PxU32 nbContactPoints, const Vec3VArg contactNormal,
	const FloatVArg invMassA, const FloatVArg angDom0, Vec3V& linVel0_, Vec3V& angState0_, PxF32* PX_RESTRICT forceBuffer, Dy::ErrorAccumulator* PX_RESTRICT globalError)
{
	Vec3V linVel0 = linVel0_;
	Vec3V angState0 = angState0_;
	FloatV accumulatedNormalImpulse = FZero();

	const Vec3V delLinVel0 = V3Scale(contactNormal, invMassA);
	
	Dy::ErrorAccumulator error;

	for(PxU32 i=0;i<nbContactPoints;i++)
	{
		const SolverContactPoint& c = contacts[i];
		PxPrefetchLine(&contacts[i],128);

		const Vec3V raXn = Vec3V_From_Vec4V(c.raXn_velMultiplierW);
		
		const FloatV appliedForce = FLoad(forceBuffer[i]);
		const FloatV velMultiplier = c.getVelMultiplier();
		const FloatV impulseMultiplier = c.getImpulseMultiplier();

		/*const FloatV targetVel = c.getTargetVelocity();
		const FloatV nScaledBias = c.getScaledBias();*/
		const FloatV maxImpulse = c.getMaxImpulse();
		
		const Vec3V v0 = V3MulAdd(linVel0, contactNormal, V3Mul(angState0, raXn));
		const FloatV normalVel = V3SumElems(v0);


		const FloatV biasedErr = c.getBiasedErr();//FScaleAdd(targetVel, velMultiplier, nScaledBias);

		// still lots to do here: using loop pipelining we can interweave this code with the
		// above - the code here has a lot of stalls that we would thereby eliminate
		const FloatV _deltaF = FMax(FNegScaleSub(normalVel, velMultiplier, biasedErr), FNeg(appliedForce));
		const FloatV _newForce = FAdd(FMul(appliedForce, impulseMultiplier), _deltaF);
		const FloatV newForce = FMin(_newForce, maxImpulse);
		const FloatV deltaF = FSub(newForce, appliedForce);

		if (globalError)
			error.accumulateErrorLocal(deltaF, velMultiplier);

		linVel0 = V3ScaleAdd(delLinVel0, deltaF, linVel0);
		angState0 = V3ScaleAdd(raXn, FMul(deltaF, angDom0), angState0);

		FStore(newForce, &forceBuffer[i]);

		accumulatedNormalImpulse = FAdd(accumulatedNormalImpulse, newForce);
	}

	linVel0_ = linVel0;
	angState0_ = angState0;

	if (globalError)
		globalError->combine(error);

	return accumulatedNormalImpulse;
}

FloatV solveExtContacts(const SolverContactPointExt* PX_RESTRICT contacts, PxU32 nbContactPoints, const Vec3VArg contactNormal,
	Vec3V& linVel0, Vec3V& angVel0,
	Vec3V& linVel1, Vec3V& angVel1,
	Vec3V& li0, Vec3V& ai0,
	Vec3V& li1, Vec3V& ai1,
	PxF32* PX_RESTRICT appliedForceBuffer,
	Dy::ErrorAccumulator* PX_RESTRICT error);

}

}

#endif